<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>两列布局</title>
  <style>
    .left {
      float: left;
      width: 300px;
      background-color: red;
    }

    .right {
      background-color: blue;
      /* 谁想要自适应-谁触发bfc */
      overflow: hidden;
      /*文字会产生自围，没办法做到两列，因此需要触发bfc*/
    }
  </style>
</head>

<body>
  <div class="left">左边定宽</div>
  <!-- 文字会被覆盖掉 -->
  <div class="right">右边自适应右边自适应右边自适应右边自适应右边自适应右边自适应右边自适应右边自适应右边自适应右边自适应</div>

</body>

</html>